The present invention relates to a mobile communication terminal and a data transmission method, each using a battery as a power source.
PDC (Personal Digital Cellular) portable phones and PHS (Personal Handy Phone System) portable phones are well known as a mobile communication terminal using a battery as a power source. Personal phones of this type can transmit and receive electronic mails using the Internet.
When the voltage of a battery acting as a power source is less than a prescribed value, conversations or electronic mails cannot be transmitted or received. In order to deal with such problems, the terminal includes a charger and informs the user of the charged state of the battery. This approach allows the user to readily charge the battery. The terminal informs the user of replacement of a battery or urges the user to replace the battery.
Conventionally, when the voltage level is less than a prescribed value during transmission of an electronic mail, transmission errors occur. This requires retrying the transmission procedure of the mail. Hence, the user is involved in unwanted troubles, that is, checking the voltage level of the power source or paying attention to the voltage level thereof every time an electronic mail is transmitted and received.